Field of Invention
The present invention relates to an electronic device. More particularly, the present invention relates to an electronic device for saving power consumption.
Description of Related Art
Most modern lighting devices have adopted incandescent bulbs or fluorescent tubes. However, as the maturity of the lighting technology or the semiconductor technology progresses, modern light emitting diode (LED) not only has high luminous efficiency but also saves on power consumption. Therefore, there is a significant demand for LEDs, which are now flourishing.
However, the current common LED driver usually consists of a direct current (DC) voltage source and a linear constant current circuit. In order to reduce loss of the linear constant current circuit, the output voltage of the DC voltage source is regulated, such that the voltage across the linear constant current circuit is controlled within a certain range to prevent the linear constant current circuit from generating an excessive loss. Due to the reference voltage for controlling the linear constant current circuit being a fixed value, the driver efficiency cannot be optimized under a light load condition.
Besides, the present LED driver usually protects the circuit by stopping the output voltage of the DC voltage source in the case it has short-circuited. However, in the application of multi-path load in parallel, the method cannot independently protect each path load of the multi-path load. Therefore, the output voltages of the other path loads are affected when one path load of the multi-path load is short-circuited. Further, the character of components in the general linear constant current circuit limits the driver. Thus, the LED driver cannot achieve a wider dimming range.